U.S. political surveys are showing that Democratic presidential candidate Hillary Clinton has regained her edge over Republican contender Donald Trump in the aftermath of last week's Democratic convention where she and a raft of other speakers attacked his credentials to be the American leader.

Trump, a real estate tycoon seeking elected office for the first time, enjoyed a similar bump in polling against Clinton, a former U.S. secretary of state, after the Republican convention two weeks ago with its barrage of taunts against her.

But now that both of the quadrennial conventions are over, CBS News said Clinton leads Trump 46 percent to 39, similar to her 43-37 lead in mid-June. The television network's poll in the days after Trump claimed the Republican nomination more than a week ago showed the race tied at 42 apiece.

Democratic vice presidential nominee Tim Kaine and Democratic presidential nominee Hillary Clinton walk through the falling balloons during the final day of the Democratic National Convention in Philadelphia, July 28, 2016.

CBS also said its latest survey shows that voters continue to hold unfavorable views of both Clinton and Trump, although both of their standings were somewhat improved after their respective conventions. Voters now hold a 36 percent to 50 percent favorable-unfavorable view of Clinton, while Trump is at 31-52.

A CNN-ORC poll released later Monday had Clinton holding an even larger lead of 52 percent to 43 percent following the Democratic National Convention. The television network's poll after the Republican convention had Trump ahead 48-45.

The CNN poll also found that Clinton's convention appears to have raised the percentage of Americans who think her policies will move the country in the right direction - from 43 percent before either convention to 48 percent now.

In another post-conventions survey, Public Policy Polling showed a 46-41 Clinton lead in polling that included two other presidential candidates, Libertarian Gary Johnson, with 6 percent support, and the Green Party's Jill Stein at 2 percent.

Republican presidential candidate Donald Trump takes the stage during the final day of the Republican National Convention in Cleveland, July 21, 2016.

"It looks like the Republican and Democratic convention bounces have cancelled each other out and basically left the race where it was a month ago,” said Dean Debnam, Public Policy Polling's president.

A third pollster, Gallup, said Americans are almost evenly divided on how they view Clinton's Democratic Party after its convention, with 44 percent feeling favorably about it and 42 percent less favorably.

But Gallup said a separate survey taken in the immediate aftermath of the Republican convention showed that only 35 percent of Americans had a more favorable view of the party, compared to 52 percent viewing it less favorably.